The present invention relates to a method of manufacturing an optical connector typified by an optical fiber array, a lens array and the like. Specifically, this invention relates to a method of manufacturing a two-dimensional optical connector component comprising various one-dimensional optical connector components being usable for optical fiber communications by positioning them with a plural number of guide pins, and then stacking them precisely.
In an optical device, an optical fiber array or other various optical connectors are used for coupling a waveguide with an optical fiber, or an optical fiber with another. The optical connector has one or more precision V-shaped grooves with the respective optical fibers aligned and fixed therein. A material for a substrate may be ceramic, glass or ceramic glass. Precision patterning is accomplished by grinding or glass pressing. Recently, the variety of switching technique or the like has been increased, and accordingly, the optical connectors have become variously configured. For example, optical fibers are aligned two-dimensionally.
In the past, various basic configurations of two-dimensional optical fiber array (referred to as a 2DFA occasionally hereinafter) have been proposed. For example, there has been known (1) a 2DFA comprising a ferrule of two-dimensional array type, (2) a 2DFA comprising a stack of V-shaped grooved substrates, (3) a 2DFA comprising a stack of one-dimensional optical fiber array (sometimes hereinafter referred to as a FA) to assure a desired number of channels and the like. However, these have problems as described below.
In the case where the two-dimensional array ferrule serves as the 2DFA, as disclosed in Japanese Patent Laid-Open No. 2-19808, a high precision is attained, although the number of cores of the ferrule is limited. However, if the ferrule includes 8- by 10- cores, for example, eighty optical fibers have to be implemented on the ferrule one by one. A hole, to which the optical fiber is to be inserted, has a clearance of only several xcexcm from the optical fiber for assuring precision. Therefore, the optical fiber may be readily cut depending on how it is handled, and thus reliability is low. Problem with the stack of v-shaped grooved substrates.
When stacking V-shaped grooved substrates to form a 2DFA, means for aligning the V-shaped grooves on the respective substrates is the most difficult problem. As an example, there is contemplated a method of forming V-shaped grooves in the respective substrates with reference to end faces thereof, and then stacking the V-shaped grooved substrates with reference to the end faces.
As shown in FIG. 8, a lowermost V-shaped grooved substrate 2 is placed abutting against a side face of an end plate 81, for example, and then, an optical fiber 8 is placed in a V-shaped groove 7. Then, a second lowest V-shaped groove substrate 2 is placed on the lowermost one, and an adhesive is applied thereon and cured. This procedure is repeated to form a two-dimensional optical fiber array 80.
According to this method, however, it is difficult to assure high precision in machining the V-shaped grooves with reference to the end faces, and thus, precision of lateral positions thereof cannot be assured. In addition, in a stacking direction, errors in thickness of the V-shaped grooved substrates are accumulated as the substrates are stacked. Therefore, a high-precision 2DFA cannot be fabricated. Additionally, since the optical fibers are implemented on the V-shaped grooved substrates while stacking of the substrates, a failure, such as cutting of the fiber, can easily result.
Another possible method of stacking the V-shaped grooved substrates to form a 2DFA is to form V-shaped grooves on both upward and downward surfaces of the substrate with aligned with each other, and implement the optical fibers thereon and stack the substrates with reference to the grooves.
As shown in FIG. 9, a plurality of V-shaped grooved substrates 94 with V-shaped grooves 7 formed on both surfaces thereof are prepared, and the optical fibers 8 are placed in the V-shaped grooves 7 of the lowermost V-shaped grooved substrate 94. Then, the second lowest V-shaped grooved substrate 94 is placed on the lowermost one, and an adhesive is applied thereon and cured. This procedure is repeated to form a two-dimensional optical fiber array 90.
According to this method also, however, errors in thickness of the substrates are accumulated, and the optical fibers are implemented on the substrates while stacking the substrates. Thus, the reliability is readily decreased.
According to the method wherein a 2DFA is formed by stacking FAs, a failure resulting from cutting of the optical fiber can be avoided because the FAs are previously fabricated. However, simply stacking the FAs cannot avoid the problem of the stacking error resulted from the thicknesses of the substrates. Thus, a means is required for fabricating the 2DFA without the stacking error in the method of stacking the FAs to form a 2DFA.
The two-dimensional alignment of a 2DFA having high reliability may be achieved by manufacturing a 2DFA by stacking FAs quite precisely so as to not make positional deviation. However, such a method has not been provided in the past.
Therefore, an object of the present invention is to provide a method of manufacturing a two-dimensional optical connector component capable of stacking a plural number of one-dimensional optical connector components, such as a FA, with high precision, thereby contributing to further construction and increased use of an optical transmission system and to development of an information society.
In order to attain the above object, the inventors have investigated various methods for precisely stacking optical connector components, such as a FA. As a result, the inventors have found that the above object can be attained by measures as described below.
According to the present invention, there is provided a method of manufacturing a two-dimensional optical connector component comprising a plural number of FAs stacked by using at least four parallel disposed guide pins, characterized in that said at least four parallel disposed guide pins are positioned by at least five pieces of beams. A one-dimensional optical connector component itself may be used as a substitute for two pieces of beams among said at least five pieces of beams.
A two-dimensional optical connector component may be manufactured by a method, which may include a step of positioning a plural number of one-dimensional optical connector components by using at least four pieces of parallel disposed guide pins. In the case where a one-dimensional optical connector component itself is used as a substitute for two pieces of beams among at least five pieces of beams, the position of the guide pins is determined by the one-dimensional optical connector component. Consequently, the one-dimensional optical connector component itself takes a role in the determination for the positioning of the one-dimensional optical connector component to be stacked.
In the above-described method of manufacturing a two-dimensional optical connector component, the positioning of the one-dimensional optical connector component refers to positioning in a direction of stacking the one-dimensional optical connector components.
In the method of manufacturing a two-dimensional optical connector component according to this invention, the two-dimensional optical connector component may be one comprising an optical medium having a substantially cylindrical shape mounted thereon, or one comprising an optical medium having a substantially cylindrical shape mounted thereon and having a guide groove for fixing the guide pin formed thereon. One example is a two-dimensional optical fiber array.
In the method of manufacturing a two-dimensional optical connector component according to this invention, in the case that a one-dimensional optical connector component itself is not used as a substitute for two pieces of beams among five pieces of beams, a guide pin jig may be used comprising at least five pieces of beams and at least four parallel disposed guide pins. In this guide pin jig, the beams comprise two pieces of vertical beam members and two pieces of transverse beam members which form a parallel cross, and two pieces of diagonal beam members provided diagonally across the parallel cross and the two pieces of vertical beam members at the minimum. A plurality of guide pins is provided at desired positions of each of the two pieces of vertical beam members. A two-dimensional optical connector component may be manufactured by a method which comprises: preparing a plurality of optical connector components each having guide grooves for fixing the guide pins at both ends thereof, inserting a first one-dimensional optical connector component into the guide pin jig so that the guide grooves are brought into contact with the respective first guide pins provided on the two vertical beam members and making the guide grooves and the guide pins contact intimately with each other under giving a load thereto; inserting a second one-dimensional optical connector component into the guide pin jigs so that the guide grooves are brought into contact with the respective second guide pins provided on the two pieces of vertical beam members and bringing the guide grooves and the guide pins into intimate contact with each other under giving a load thereto; injecting an adhesive into a space between the first one-dimensional optical connector component and the second one-dimensional optical connector component and curing the adhesive, and then repeating the last two steps until the necessary numbers of one-dimensional optical connector components are stacked.
As a method for applying a load, one may employ a method of applying a load in a direction of gravitation to the one-dimensional optical component being contact intimately with the guide pin, or a method of applying a load by pinching the guide pin and a one-dimensional optical component being contact intimately with the guide pin. In the case that a load is applied by pinching the guide pin and a one-dimensional optical components being contact intimately with the guide pin, it is preferable to use a flexible jig having a double-pointed tack like shape.
Moreover, it is preferable that an ultraviolet curing adhesive is poured into a space between a first one-dimensional optical connector component and a one-dimensional second optical connector component and curing the adhesive with an ultraviolet ray applied to an optical medium, wherein the said one-dimensional optical components are disposed with said optical medium having a substantially cylindrical shape between the guide grooves at both ends, and the adhesive used therefore is an ultraviolet curing adhesive. It is preferable to pour the adhesive into a region except for the guide grooves. This is because the guide pins are undesirably fixed if the adhesive flows into the guide grooves.
According to this invention, there is provided a guide pin jig usable for manufacturing a two-dimensional optical connector component by stacking a plurality of one-dimensional optical connector components. The jig is comprised of at least four parallel disposed guide pins and at least five beams members, in which the guide pins are positioned by the five beams members.
According to this invention, there is also provided a double-pointed tack shaped guide pin jig usable for manufacturing a two-dimensional optical connector component by stacking a plurality of one-dimensional optical connector components. The jig has an upper jaw and a lower jaw and a double-pointed tack like shape in at least one cross section thereof. The upper jaw and lower jaw are made of an elastic body. One-dimensional optical connector components and guide pins are fixed in the guide grooves and are able to be positioned between the upper and lower jaws.